Chapter-3,Biology-classification.pptx bio

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1. Swami Keshvanand Institute of Technology, Management & Gramothan , Jaipur B.Tech . IV Semester Biology 4EE2-01 Credit: 2 Max. Marks: 100 (IA: 20 , ETE: 80) Presented by Prof. Archana Saxena Department of Chemistry

2. RAJASTHAN TECHNICAL UNIVERSITY, KOTA I V Semester Electrical Engineering 4EE2-01: Biology Credit: 2 2 L Max. Marks: 1 00 ( IA: 2 , ETE: 8 ) End Term Exam: 3 Hours SN CONTENTS Hours 1 Introduction: Objective, scope and outcome of the course. 1 2 Introduction: Purpose: To convey that Biology is as important a scientific discipline as Mathematics, Physics and Chemistry. Bring out the fundamental differences between science and engineering by drawing a comparison between eye and camera, Bird flying and aircraft. Mention the most exciting aspect of biology as an independent scientific discipline. Why we need to study biology? Discuss how biological observations of 18th Century that lead to major discoveries. Examples from Brownian motion and the origin of thermodynamics by referring to the original observation of Robert Brown and Julius Mayor. These examples will highlight the fundamental importance of observations in any scientific inquiry.         1 3 Classification: Purpose: To convey that classification per se is not what biology is all about. The underlying criterion, such as morphological, biochemical or ecological be highlighted. Hierarchy of life forms at phenomenological level. A common thread weaves this hierarchy Classification. Discuss classification based on (a) cellularity- Unicellular or multicellular (b) ultrastructure prokaryotes or eucaryotes . (c) energy and Carbon utilization -Autotrophs, heterotrophs, lithotropes (d) Ammonia excretion- aminotelic , uricotelic , ureotelic (e) Habitata - acquatic or terrestrial (e) Molecular taxonomy- three major kingdoms of life. A given organism can come under different category based on classification. Model organisms for the study of biology come from different groups. E.coli , S.cerevisiae , D. Melanogaster, C. elegance, A. Thaliana, M. musculus         3

3. Chapter-3 Classification

4. Content Biological Classification (Taxonomy) Various criteria of classification Hierarchy of life forms at phenomenological level Classification based on cellularity, cell type, energy & carbon utilization, ammonia excretion, habitat, molecular taxonomy etc. Model organisms for study of biology

5. Biological Classification (Taxonomy) The art of identifying distinctions among organisms and placing them into groups that reflect their most significant features and relationship is called biological classification The study of one organism of a group gives us the idea about the rest of the members of that particular group. Scientists who study and contribute to the classification of organisms are known as taxonomists and their subject is called taxonomy . Taxonomy is the study of diversity of organisms and all their comparative and evolutionary relationships, based on comparative anatomy, comparative ecology, comparative physiology and comparative biochemistry.

6. Biological Classification (Taxonomy) Taxonomic knowledge about the organisms is based on their form and structure (morphology), cell (cytology), development process (embryology) and ecological relationships. This knowledge gained through taxonomy is assembled for future use not only for the biologists but also for other working in the field of medicine, agriculture and forestry or industry and so on. In order to understand the living world specifically its diversity, it is essential to make inventory of organisms with correct identification of names.

7. Criteria of classification In order to identify and classify organisms, we need to know about their characteristics. The criteria can be based on morphological, biochemical, physiological, ecological and genetic characteristics.

8. Morphology Structural features cell shape, size, colony morphology, appendages etc.) based classification

9. Ecology Classification based on surrounding environment i.e. temperature, pH, oxygen, osmotic concentration etc.

10. Physiology and metabolism Classification based on requirement for growth characters like C and N sources, cell wall constituents, general nutritional types, optimum growth temperature and mortality etc.

11. Hierarchy of life forms at phenomenological forms Atom Molecule Macromolecules(e.g. DNA) ( Polymerization ) Can form aggregates within a cell, surrounded by membrane ( organelle ) e.g. mitochondria Cell

12. Cell (Combine) Tissue (group of similar cells carrying out similar or related functions) Organs (Collections of tissues performing similar functions) Organ system (Circulatory system)

13. Organisms Population (All organisms of any area of same species) Community (Sum of populations inhabiting a particular area) Ecosystem (Living and non living both) Biosphere (Land, water, atmosphere)

14. Cell Tissues Multicellular Single celled Prokaryotic Eukaryotic (single celled or colonial (Membrane o rganisms that do not have bound nuclei) Membrane bound nuclei)

15. Classification of organisms based on cellularity Organisms Unicellular Multicellular (Single celled organisms, (Made up of more than Oldest form of life, existed one cell About 3.8 million year ago e.g. plants, animals, e.g. Bacteria, Protozoa, algae) Unicellular algae and fungi)

16. Classification based on energy and carbon utilization Organisms Autotrophs Heterotrophs Lithotrophs

17. Autotrophs Able to make organic compounds directly from inorganic materials Two types: Photoautotrophs: Uses sunlight, photosynthesis for food preparation, e.g. green plants, algae 2. Chemoautotrophs: Uses chemical energy in chemosynthesis (oxidise inorganic compounds to organic compounds) e.g. some bacteria and fungi

18. Heterotrophs Obtain their nutrients from organic material prepared by autotrophs Animals: Ingest their food and digest it internally. Fungi: Releases digestive enzymes to their surroundings and then absorb the nutrients. Saprophages : Breakdown the organic material of dead organisms, e.g. Amphitrites (worms)

19. Lithotrophs Rock eater or consumer Make use of inorganic reduced compounds as a source of energy. The process is accomplished through oxidation and ATP synthesis. Fixation of CO 2 through the Carbon cycle. C enters as CO 2 and forms glucose. e.g. Nitrifying bacteria, sulphur, iron and hydrogen oxidizers.

20. Examples of chemolithotrophic pathways Type of Bacteria Examples Reaction (e-donor/energy source) Nitrosifying Nitrosomonas NH 3 NO 2 - + e - Nitrifying Nitrobacter Azotobactor NO 2 - NO 3 - + e - Sulphur oxidizing Rhodobacteraceae , Thiotrichaceae Rhodobactor S SO 4 2- + e -

21. Classification on the basis of Nitrogen excretion After protein metabolism, nitrogen from organisms is eliminated as nitrogenous waste-Ammonia, urea, uric acid and cretanine . In many animals, urine is the main route of excretion and in some feces .

22. Amminotelic Organisms which excrete NH 3 and NH 4 + are ammonotelic . Protein carbohydrate NH 2 NH 3 Oxidation NH 3 is very toxic and soluble in water. About 0.5 L of water is needed for 1 g of nitrogen to maintain NH 3 levels in the excretory fluid below the level in body fluids to prevent toxicity. Marine organisms excrete NH 3 directly into the water. e.g. Protozoans, crustaceans (crab, prawn), polyhelminthes (tape worm), poriferans (sponges), echnionoderms (starfish, sea urchin) and other aquatic invertebrates.

23. Ureotelic Many amphibians and mammals convert ammonia to urea (process occurs in liver and kidney) Urea is less toxic than ammonia and requires less water to excrete 1g of nitrogen.

24. Uricotelic Birds, insects, lizards and snakes convert urea to uric acid. Uric acid is less toxic than urea. 0.001 L water is required per g of nitrogen Uric acid is least soluble in water, can be stored in cells and body without toxic effects. Uricotelic organisms have white pasty excreta.

25. Classification based on habitat Habitat is a natural environment characterized by both physical and biological features, places where a species can find food, shelter, protection and mates for reproduction. 4 categories: Aquatic Terrestrial Amphibians Arboreal

26. Aquatic Fresh water: e.g. hito , dalag , crabs, prawns, lobsters Lentic (slow moving) Pelagic zone or littoral zone (shallow zone, rooted plants) Photic zone or limnetic zone (open water zone, photosynthetic algae) Aphotic zone or profundal zone

27. Aquatic Lotic (fast moving) Wet land (saturated)

28. Sea water habitat Oceanic: Vast open part, whale and shark Benthic: Below water, invertebrates Intertidal: sea stars, crabs Neritic: Near shore, fish spp.

29. Classification on the basis of cell structure: Prokaryotic, Eukaryotic Comparison of Prokaryotic and Eukaryotic cells Feature Prokaryotic Eukaryotic Extra-cellular structures 1. Cell wall Peptidoglycan found on cell wall Cellulose, chitin and both on plants and fungal cells 2. External layer Capsule/slime Pellicle (thin skin) 3. Flagella Present in some Occasionally present (9+2 arrangement) 4. Cilia Absent Occasionally present, shorter than flagella 5. Pili Sometimes present as attachment Absent

30. Feature Prokaryotic Eukaryotic Intracellular structures 1. Mitotic spindle Absent Present during cell division 2. Plasma membrane Fluid mosaic lacking sterols Fluid mosaic with sterols 3. Cytoplasm Present Present 4. Internal membranes Only in photosynthetic organisms Membrane enclosed organelle 5. Endoplasmic reticulum Absent Present 6. Respiratory enzymes On cell membrane On mitochondria 7. Chromatophores In photosynthetic bacteria Absent 8. Chloroplasts Absent In plant cells 9. Golgi apparatus Absent Present 10. Lysosomes, mitochondria, vacuoles, peroxisomes Absent Present 11. Ribosomes 70 S 80 S in cytoplasm and |ER, 70S in chloroplasts and mitochondria

31. Feature Prokaryotic Eukaryotic Reproductive system 1. Cell division Binary fission Mitosis and meiosis 2. Reproduction type Asexual Sexual and Asexual Genetic structure 1. DNA Single circular chromosome Paired linear chromosomes 2. Location of genetic information Not membrane bound Membrane bound nucleus 3. Nucleolus, histones Absent Present 4. Trachosmosomal DNA As plasmid In mitochondria, plastid, plasmid

32. History of classification Pre- Linnenean classification: Given by Aristotle, Theophrastus (Father of Botany)-Used only morphological traits for classification. Two kingdom classification: By Carolus Linnaeus (father of taxonomy)-Based on morphological and anatomical traits-Plants and animals.

33. Three kingdom classification Classification given by Hackel Animals Plants Protista (Bacteria, Protozoa, fungi, many algae and sponges)

34. Four kingdom classification Given by Margulis and Copeland Monera : All prokaryotes, bacteria, blue green algae Protista: Eukaryotic algae, fungi, protozoa Plantae: All green plants Animalia : Animals derived from zygote

35. Six Kingdom classification Given by Carl Woese , Criteria of classification was cell type, ability to make food and no. of cells in the body Eubacteria Archaebacteria Protista Plantae Animalia Fungi

36. Model organisms for the study of biology Saccharomyces cerevisiae (fungi): Species of yeast, used in wine making, baking and Brewing. Isolated from skin of some fruits like plum, grapes. It is one of the most intensively studied eukaryotic model organism in molecular & cell biology. It is responsible for fermentation. Used as model organism due to Single celled, easily cultured Divides with meiosis, can be used for sexual genetic research. Complex eukaryotic structure Used in the study of aging, meiosis, recombinant DNA repair, genome sequencing, gene function and interaction .

37. Drosophila melanogaster Fruit fly, first gene mapping was done on it, which provided the evidence for the chromosome theory of inheritance. Reasons for use in laboratory Easily cultured and readily anesthetized, short generation time (10 days), easy morphology Male and females are easily distinguishable. Only four pair of chromosomes, 3 autosomes and one air of sex chromosomes Males do not show meiotic recombination facilitating genetic studies. Genome similar to humans.

38. Caenorhabditus elegans Free living transparent nematode, 1 mm length, lives in temperate environment. It is an unsegmented pseudocoelom and lacks respiratory or circulatory system. Research on this animal has been done in the area of neuronal development. It was the first multicellular organism to have its whole genome sequenced. Neurons of humans and C. elegance are almost identical.

39. Escherichia coli Bacteria, found in lower intestine of warm-blooded animals. Most widely used prokaryotic model organism Reasons to be studied as model organism: Ease of culture and manipulation Creation of recombinant DNA Researchers can introduce genes into the microbes using plasmids which permit high level expression of proteins which may be mass produced in industrial fermentation process e.g. production of insulin.

40. Arabidopsis thaliana Small road side flowering plant ((Angiosperm), belongs to Brassicacae . As model organism: First plant, whose genome was sequenced. Small genome.

41. Mus musculus House mouse, high homology with humans Mutations can be done in its genome. For modelling human disease and comparative genome analysis .

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